import { EventSpecCoordinates, EventSpecResponse } from "./AvoEventSpecFetchTypes";
/**
 * The key of a fetch with gateway coordinates, or undefined without any: "\0" and a JSON
 * array of `parts` then both normalized coordinates (null for an absent one). JSON encodes
 * every part on its own, so no event name can make it equal another key; and as the
 * apiKey never contains NUL, no key without coordinates starts with "\0".
 * Shared by the spec cache key and the fetcher's in-flight dedupe key.
 */
export declare const coordinatesKey: (parts: string[], coordinates?: EventSpecCoordinates) => string | undefined;
/** Trims each coordinate and drops a blank or non-string one. */
export declare const normalizeCoordinates: (coordinates?: EventSpecCoordinates) => EventSpecCoordinates;
/** TTL of a fetch that failed other than with a 404, so a blip skips validation only briefly. */
export declare const TRANSIENT_FAILURE_TTL_MS = 5000;
export declare class AvoEventSpecCache {
    private cache;
    private globalEventCount;
    /**
     * The key of one spec. Gateway coordinates are part of it, so a gateway-input spec and an
     * output spec for the same event name never share an entry; without coordinates the key
     * is the plain `apiKey\0streamId\0eventName`.
     */
    static makeKey(apiKey: string, streamId: string, eventName: string, coordinates?: EventSpecCoordinates): string;
    /**
     * Returns the cached EventSpecResponse, or undefined on cache miss.
     * A cached response with eventSpec: null means "no spec exists for this event";
     * a cached null means the fetch failed (such as a 404), so the event is not validated.
     */
    get(key: string): EventSpecResponse | null | undefined;
    /**
     * Returns true if the key exists in the cache and has not expired.
     */
    contains(key: string): boolean;
    /**
     * Stores a fetched spec, or null for a failed fetch. A spec is kept until its TTL or
     * MAX_EVENT_COUNT uses; a null until its TTL only. `ttlMs` defaults to 60 s; a transient
     * failure passes TRANSIENT_FAILURE_TTL_MS.
     */
    set(key: string, value: EventSpecResponse | null, ttlMs?: number): void;
    flush(): void;
    private purgeExpired;
    private evictLRU;
}